1. Field of the Invention
The invention relates to an automotive electrical connection box.
2. Description of the Related Art
Japanese Unexamined Patent Publication H10-302887 and FIG. 6 herein disclose an automotive electrical connection box. With reference to FIG. 6, the electrical connection box has a lower casing 1 and an upper casing 2 with surrounding walls that are coupled together. The coupled casings 1 and 2 are mounted to a lower cover 3. Connectors 4 are provided in the lower cover 3 and at least partly surround a bolt insertion portion 5. A bolt B is introduced through the casings 1, 2 and is screwed into the bolt inserting portion 5. Thus, the coupled lower and upper casings 1, 2 are fixed to the lower cover 3.
The bolt B can be detached upward to release the lower and upper casings 1, 2 from the fixed state. Thus, the lower and upper casings 1, 2 can be detached integrally from the lower cover 3.
However, the lower and upper casings 1, 2 are not raised automatically and detached from the lower cover 3 as the bolt B is detached. Thus, an operator must perform additional steps to detach the lower and upper casings 1, 2 from the lower cover 3.
The bolt B is not assembled with the lower and upper casings 1, 2 beforehand. Rather, the bolt B must be inserted through the assembled casings 1, 2 to fix the casings 1, 2 to the lower cover 3. Accordingly, a parts administration problem exists.
FIG. 7 shows an electrical connection box that has been proposed to avoid the above-described problems. More particularly, the proposed electrical connection box enables a lower casing 1 and an upper casing 2 to be detached from a fixing member simultaneously with a bolt detaching operation and also enables a bolt to be assembled with the lower and upper casings 1 and 2 beforehand. The lower and upper casings 1, 2 are coupled lockingly together by locks on their surrounding walls and are fixed to a fixing member 6, such as a vehicle body, a holder or a lower cover by a bolt B that is introduced into substantially center portions of the casings 1, 2 beforehand.
The bolt B is introduced through a collar 7 that extends from the peripheral edge of a bolt hole of the lower casing 1. The upper casing 2 is formed integrally with a bolt inserting portion 2a. An upper part of the bolt insertion portion 2a is a small hole 2a-1 and the lower part of the bolt inserting portion 2a is a large hole 2a-2. The step between the small and large holes 2a-1 and 2a-2 contacts the upper surface of a head Ba of the bolt B. The large hole 2a-2 surrounds the outer peripheral surface of the bolt head Ba with a clearance. The bolt B is assembled beforehand so that the upper and lower surfaces of the head Ba are held rotatably between the step adjacent the small hole 2a-1 and the upper end surface of a flange 7a of the collar 7.
An impact wrench (not shown) can be inserted into the small hole 2a-1 of the bolt inserting portion 2a of the upper casing 2 from above to turn the head Ba of the bolt B and to screw the bolt B down into a nut N embedded in the fixing member 6. Thus the casings 1, 2 are fixed to the fixing member 6.
The impact wrench also can be inserted into the bolt inserting portion 2a of the upper casing 2 from above to turn the bolt head Ba in a reverse direction. As a result, the bolt B is raised and disengaged from the nut N. Additionally, the upper end surface of the bolt head Ba pushes up against the step below the small hole 2a-1 of the upper casing 2. Thus, the upper casing 2 is moved up and away from the fixing member 6. The lower casing 1 is coupled to the upper casing 2 and hence moves up with the upper casing 2. Accordingly, the lower and upper casings 1, 2 are intended to be detached integrally from the fixing member 6.
The casings 1, 2 may be large and the single bolt B may be spaced from the locks on the surrounding walls. Thus, the bolt B pushes up only a middle part of the upper casing 2. Accordingly, a part of the upper casing 2 near the bolt may deform up, and the locks on the surrounding walls may disengage from the lower casing 1 due to this deformation of the upper casing 2. As a result, only the upper casing 2 may detach with the bolt B, and the lower casing 1 may remain fixed to the fixing member 6.
Further, the upper and lower casings are coupled only at the surrounding walls, even in a bolt-fastened state. Accordingly the upper and lower casings are likely to shake with respect to each other at the middle parts distanced from the surrounding walls of large electrical connection box.
The invention was developed in view of the above problems, and an object thereof is to improve operability during the mounting/dismounting of the electrical connection box to a fixing member, such as a holder.